Pheochromocytoma is a rare type of neuroendocrine tumour that develops inside the adrenal glands, which sit on top of the kidneys. These types of tumours develop from chromaffin cells, which produce catecholamine hormones. These hormones, which include dopamine, epinephrine (adrenaline) and norepinephrine, are commonly referred to as the ‘fight or flight’ hormones.
Neuroendocrine cancers are a complex group of tumours that develop in the neuroendocrine system, which is responsible for regulating important bodily functions such as heart rate, blood pressure and metabolism. They most commonly develop in the gastro-intestinal tract, pancreas, and the lungs; however, they can develop anywhere in the body. These tumours develop from neuroendocrine cells, which are responsible for receiving signals from the nervous system and producing hormones and peptides (small proteins) in response.
There are two primary types of pheochromocytoma. The most common type is adrenal pheochromocytoma, which is often shortened to pheochromocytoma. This type of tumour develops in the inner portion of the adrenal glands, or more specifically, the adrenal medulla. Most adrenal pheochromocytomas are functional tumourstumours that produce and secrete hormones, however, some are non-functional tumourstumours that do not produce and secrete hormones and are asymptomatic. The less common type of pheochromocytoma is called an extra-adrenal pheochromocytoma, or paraganglioma. These types of tumours develop outside of the adrenal glands. This page will solely focus on pheochromocytomas.
Pheochromocytomas are most commonly diagnosed in adults between the ages of 30 and 50. However, they can be diagnosed at any age.
Treatment
If a pheochromocytoma is detected, it will be staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (node) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for pheochromocytomas may include:
- Surgery to remove as much of the tumour as possible (will vary based on location).
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells, potentially including peptide receptor radionuclide therapy (PRRT)a targeted cancer treatment that uses radioactive substances (radionuclides) to deliver radiation directly to tumour cells.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Hormone therapymedication that alters the levels of certain hormones in the body, such as oestrogen and progesterone.
- Targeted therapymedication that targets specific molecular features of cancer cells.
- Cryotherapythe process of freezing off cancerous tumours and/or lesions using liquid nitrogen.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Risk factors
The risk factors for pheochromocytoma are often associated with having certain medical conditions, including:
- Multiple endocrine neoplasia 2 syndrome (MEN2A and MEN2B).
- Von Hippel-Lindau (VHL) syndrome.
- Neurofibromatosis type 1 (NF1).
- Carney-Stratakis dyad.
- Carney triad.
Other risk factors for this disease include:
- Family history of paragangliomas and/or pheochromocytomas.
- Chronic hypoxia (most commonly found in people living at high altitudes).
- Mutations of the succinate dehydrogenase (SDH) gene.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Some of the information regarding risk factors was obtained from the Pheochromocytoma page published by the National Cancer Institute.
Symptoms
Some people with pheochromocytoma are asymptomatic.
Patients with symptomatic pheochromocytoma may experience these common symptoms:
- Hypertensionhigh blood pressure.
- Headaches.
- Unexplainable sweatiness.
- Tachycardia.
- Shakiness.
- Being very pale.
- Anxiety.
- Heart palpitations.
- An adrenal mass.
Some less common symptoms of pheochromocytoma include:
- Orthostatic hypotensionlow blood pressure.
- Vision blurring.
- Unexplained weight loss.
- Polyuriafrequent urination.
- Constipation.
- Cardiomyopathy.
- Hyperglycaemiahigh blood sugar.
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
Pheochromocytoma and Pregnancy
Pheochromocytoma during pregnancy is often mistaken for the condition pre-eclampsia, which is a common pregnancy complication characterised by hypertension and proteinuriaexcess protien in urine. A misdiagnosis in pregnant patients with pheochromocytoma can cause serious complications in both the mother and the foetus, and in extreme cases may be fatal. Early diagnosis and proper management are essential for favourable outcomes.
If fertility is important to you, and you have a familial history of pheochromocytoma or are concerned about potentially having this condition, see your GP.
Diagnosis
If your doctor suspects you have a pheochromocytoma, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Endocrine studies.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Imaging tests, potentially including:
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- PET (positron emission tomography) scana type of medical imaging that uses radioactive tracers to create detailed images of the body.
- Exploratory surgerya surgical procedure used for conditions that cannot be confirmed by scans and tests alone.
Exploratory Surgery
After conducting the previously mentioned diagnostic tests, your doctor may strongly suspect that you have a pheochromocytoma. In most cases, a diagnosis can be confirmed after a biopsyremoval of a section of tissue to analyse for cancer cells, where a section of tissue is removed and analysed for cancer cells. However, doctors avoid conducting a biopsy in patients who have suspected pheochromocytomas as there is a heightened risk of complications, such as haemorrhages, hypertensive crisis, and the spread of cancer cells. Instead, diagnosis relies heavily on imaging tests and endocrine studies, with biopsies only being considered in extremely rare circumstances.
Once the tumour has been removed, it will be sent to a laboratory and analysed for cancer cells.
